Grommet and wire harness

ABSTRACT

A grommet that includes a main body configured to fit into a through hole in a wall and come into contact with a circumferential edge of the through hole; and a reinforcement provided in a through space in the main body and configured to suppress inward distortion of the main body, the through space being open in a same direction as a penetrating direction of the through hole.

This application is the U.S. National Phase of PCT/JP2017/020773 filedJun. 5, 2017, which claims priority to JP 2016-125168 filed Jun. 24,2016, the entire disclosure of which is incorporated herein byreference.

BACKGROUND

The present disclosure relates to a grommet and a wire harness.

Conventionally, a wire harness equipped with a grommet that can beattached to a through hole which is formed in a wall of a vehicle body,for example, and through which a wire passes, is known (as disclosed inJP 2015-42023A, for example). The intrusion of water into the inside ofthe wall from the through hole can be prevented by attaching the grommetto the through hole. This grommet has a cylindrical portion that can befitted into the through hole, and the cylindrical portion is configuredto come into close contact with a circumferential edge portion of thethrough hole.

SUMMARY

However, with the above-described configuration, there is concern thatthe cylindrical portion will be distorted inward by, for example, stressthat is applied to the grommet due to a vehicle layout or high-pressurecleaning water that is sprayed onto the grommet during high-pressurecleaning. If the cylindrical portion is distorted inward, the adhesionto the circumferential edge of the through hole is no longer maintained,and the waterproofness may deteriorate.

An exemplary aspect of the disclosure provides a grommet and a wireharness that can prevent deterioration of waterproofness.

A grommet according to the present disclosure includes a main bodyconfigured to fit into a through hole in a wall and come into contactwith a circumferential edge of the through hole; and a reinforcementprovided in a through space in the main body and configured to suppressinward distortion of the main body, the through space being open in thesame direction as a penetrating direction of the through hole, whereinthe reinforcement member is cylindrical and conforms to an innercircumferential surface of the main body, and is accommodated in thethrough space, and the inner circumferential surface of the main bodyincludes a second circumferential surface that is located in closeproximity to, or abuts against, an outer circumferential surface of thereinforcement and a first circumferential surface that is inclined sothat an opening width of the main body gradually decreases from thesecond circumferential surface toward an end of the main body in anaxial direction thereof.

A wire harness according to the present disclosure includes a pluralityof wires; a sheath that encloses the plurality of wires collectively;and the grommet.

According to the present disclosure, the shape of the main body ismaintained by the reinforcement, and the adhesion to the circumferentialedge of the through hole is maintained. Thus, deterioration ofwaterproofness can be prevented.

Moreover, in the grommet according to the present disclosure, thereinforcement is cylindrical and conforms to the inner circumferentialsurface of the main body, and is accommodated in the through space. Withthis configuration, the shape of the main body can be maintained and thedeterioration of waterproofness can be prevented by performing a simpleoperation of merely accommodating the reinforcement in the throughspace.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing a portion of a wire harness according toan embodiment of the present disclosure, the portion extending from anexterior side to an interior side of a vehicle.

FIG. 2 is an enlarged cross-sectional view showing a portion of the wireharness, the portion extending from the exterior side to the interiorside of the vehicle.

FIG. 3 is a perspective view showing a grommet.

FIG. 4 is a front view showing the grommet.

FIG. 5 is a plan view showing the grommet.

FIG. 6 is a cross-sectional view showing the grommet.

FIG. 7 is a partially enlarged cross-sectional view of the wire harnessand shows a state in which a sealing portion of the grommet is in closecontact with a corrugated tube.

DETAILED DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the present disclosure will be described below.

The grommet according to the present disclosure may also have aconfiguration in which the reinforcement member (reinforcement) is acorrugated tube that passes through the main body portion (main body),and an outer circumferential surface of the corrugated tube is in closecontact with the inner circumferential surface of the main body portion.With this configuration, a liquid-tight joint can be obtained betweenthe grommet and the corrugated tube without having to perform aconventional operation of fixing an end portion of a corrugated tube toa grommet.

Embodiment

Hereinafter, an embodiment of the present disclosure will be describedin detail with reference to FIGS. 1 to 7.

A grommet 10 according to this embodiment is included in a wire harness30 that connects a device installed in a front portion of a vehicle bodyof a vehicle, such as a hybrid automobile, and a device installed in arear portion of the vehicle body to each other. The wire harness 30 ismostly disposed under the floor of the vehicle body, and passes througha wall 40 of the vehicle body and is connected to a device locatedinside the vehicle.

The wire harness 30 includes a plurality of wires 31 and a sheathingmember (sheath) that encloses the plurality of wires 31 collectively.Each of the wires 31 is constituted by a conductor and an insulatingcoating that encloses the outer periphery of the conductor, and hasfavorable flexibility. Terminal fittings that can be connected torespective devices are connected to both end portions of each wire 31.The sheathing member may be a pipe 32, a corrugated tube 33, and thelike that are made of a synthetic resin or a metal. The pipe 32 mainlyencloses a portion of the wires 31 that is disposed under the floor(outside the vehicle) and protects the wires 31. The corrugated tube 33is connected to an end portion of the pipe 32 and encloses a portion ofthe wires 31 that is desired to be freely bendable, or, mainly a portionof the wires 31 that is disposed above the floor (inside the vehicle).

The corrugated tube 33 is made of a synthetic resin and is a freelybendable, bellows-like tube member in which ridge portions 34 and valleyportions 35 are successively provided in an axial direction thereof. Thecorrugated tube 33 is joined to the end portion of the pipe 32 using aconnecting member 36 such as a rubber bush, a cable tie, and the like,in a state in which waterproofness is ensured. The corrugated tube 33has a circular cross-sectional shape.

The grommet 10 is made of a rubber, is attached to the wall 40 of thevehicle body and axially seals the through hole 41 in the wall 40. Thegrommet 10 has a main body portion 11 that is fitted into the throughhole 41 in the wall 40 and that comes into close contact with thecircumferential edge portion of the through hole 41. The main bodyportion 11 has a flat cylindrical shape with its length in the axialdirection being slightly smaller than its length in the direction thatis approximately perpendicular to the axial direction. Opposite faces ofthe main body portion 11 in the axial direction are approximatelyparallel to each other.

A through space 12 is formed in the main body portion 11, the throughspace 12 being open to both sides in the axial direction of the mainbody portion 11. The through space 12 in the main body portion 11 iscompletely open at both ends thereof in the axial direction of the mainbody portion 11. The through space 12 has substantially the samecircular cross-sectional shape as the through hole 41 in the wall 40.

As shown in FIG. 6, an inclined surface (hereinafter referred to as a“first circumferential surface 14”) is formed at one end side in theaxial direction of the inner circumferential surface of the main bodyportion 11, the inclined surface being inclined so that the openingwidth gradually decreases toward the end. Moreover, a surface(hereinafter referred to as a “second circumferential surface 15”) thathas a constant opening width in the axial direction, or in other words,that is approximately parallel to the axis of the main body portion 11is formed at a portion of the inner circumferential surface of the mainbody portion 11 excluding the first circumferential surface 14.

The main body portion 11 is provided with an outer flange portion 16 andan inner flange portion 17 that are disposed on the exterior side andthe interior side, respectively, when attached to the wall 40. The outerflange portion 16 and the inner flange portion 17 protrude radiallyoutward from the main body portion 11. In a state in which the grommet10 is attached to the wall 40, the outer flange portion 16 is in closecontact with the outer wall surface of the wall 40, the inner flangeportion 17 is in close contact with the inner wall surface of the wall40, and the wall 40 is thus elastically sandwiched between the outerflange portion 16 and the inner flange portion 17.

The outer flange portion 16 is provided at an end portion (end portionon the exterior side) of the main body portion 11 in the axial directionand extends along the entire circumference of the main body portion 11.The outer flange portion 16 is thicker than the main body portion 11. Anouter abutment portion 18 is provided at an outer edge portion of theouter flange portion 16. The outer abutment portion 18 extendscontinuously along the entire circumference of the outer flange portion16, and elastically comes into close contact with the wall surface ofthe wall 40 when the grommet 10 is attached to the wall 40.

The inner flange portion 17 has a smaller external diameter than theouter flange portion 16. Moreover, a tapered portion 13 is formed on oneend side (front end side in a direction of attachment to the wall 40) inthe axial direction of the main body portion 11 such that the externaldiameter gradually decreases toward that end.

As shown in FIG. 3, the main body portion 11 is provided with aprotruding portion 21 that is formed by a portion of the main bodyportion 11 in the circumferential direction protruding outward. Theprotruding portion 21 is a thick portion spanning from the inner flangeportion 17 to the tapered portion 13. The protruding portion 21 isshaped like a rib with a substantially triangular cross-sectional shape.

As shown in FIG. 5, the main body portion 11 is provided with astrip-shaped portion 22 that protrudes in the axial direction from anend edge of the main body portion 11. The protruding length of thestrip-shaped portion 22 is set to be equal to the length of the mainbody portion 11 in the axial direction, and the width (length in thecircumferential direction of the main body portion 11) of thestrip-shaped portion 22 is set to be equal to the width of theprotruding portion 21. The strip-shaped portion 22 is disposed at thesame position as the protruding portion 21 with respect to thecircumferential direction of the main body portion 11, and is lined upwith the protruding portion 21 in the axial direction. The strip-shapedportion 22 is formed by a portion of the main body portion 11 in thecircumferential direction extending in the axial direction, and has acircular-arc cross-sectional shape that is curved along the end edge ofthe main body portion 11. A projecting rim portion 27 that protrudesradially outward is provided at a protruding end portion of thestrip-shaped portion 22. The projecting rim portion 27 is formed alongthe entire width of the strip-shaped portion 22.

As shown in FIG. 2, the main body portion 11 is provided with a sealingportion 24 that can come into close contact with the outercircumferential surface of the corrugated tube 33. The sealing portion24 is formed in a portion of the main body portion 11 that comes intoclose contact with the wall 40.

As shown in FIG. 6, the sealing portion 24 has a plurality (two, in thisembodiment) of lip portions 26 that protrude from the innercircumferential surface of the main body portion 11. The plurality oflip portions 26 protrude substantially upright from the secondcircumferential surface 15, and are arranged at predetermined intervalsin the axial direction of the main body portion 11. One lip portion 26of the plurality of lip portions 26 is provided inside the inner flangeportion 17, and the other lip portions 26 are provided inside the outerflange portion 16.

Each of the lip portions 26 protrudes inward from the innercircumferential surface of the main body portion 11 and extendscontinuously in the circumferential direction. Each lip portion 26 has amountain-shaped cross-sectional shape that can be inserted into a grooveportion of the corrugated tube 33. The width (length in the axialdirection of the main body portion 11) of each lip portion 26 graduallydecreases toward its protruding end. Both side faces (both faces in theaxial direction of the main body portion 11) of each lip portion 26 comenearer to each other toward the protruding end with generally the sameslope. A protruding end surface of each lip portion 26 is approximatelyparallel to the second circumferential surface 15.

The plurality of lip portions 26 have the same shape with equalprotruding lengths. The protruding length of the lip portions 26 is setto be slightly larger than the depth (recessed length) of the valleyportions 35 of the corrugated tube 33.

A reinforcement member 25 that suppresses inward distortion of the mainbody portion 11 is provided in the main body portion 11. Thereinforcement member 25 is the corrugated tube 33 and passes through thethrough space 12.

Next, an example of an operation for assembling the wire harness 30according to this embodiment will be described.

First, the outer periphery of the wires 31 is enclosed by a sheathingmember. The plurality of wires 31 are bundled together and inserted intothe pipe 32, the corrugated tube 33, or the like. Moreover, the pipe 32and the corrugated tube 33 are joined to each other in the axialdirection using the connecting member 36.

Next, the grommet 10 is attached to the wire harness 30. The corrugatedtube 33 is inserted and fitted into the through space 12 of the grommet10, and the sealing portion 24 of the grommet 10 is in close contactwith the outer circumferential surface of the corrugated tube 33. Morespecifically, as shown in FIG. 7, the lip portions 26 of the sealingportion 24 are inserted into the valley portions 35 of the corrugatedtube 33, the protruding end surfaces of the lip portions 26 elasticallyabut against bottom surfaces (inner surfaces) of the valley portions 35,and the lip portions 26 are in close contact with the corrugated tube 33over the entire circumference thereof. Moreover, end surfaces of theridge portions 34 of the corrugated tube 33 are located in closeproximity to, or abut against, the inner circumferential surface of themain body portion 11, and the ridge portions 34 and the lip portions 26mesh with each other in the axial direction. At this time, at least thefirst circumferential surface 14 of the main body portion 11 is in closecontact with the end surfaces of the ridge portions 34 of the corrugatedtube 33.

Then, a fixing means such as a piece of tape is wrapped around thestrip-shaped portion 22 of the grommet 10 and the outer circumferentialsurface of the corrugated tube 33 to thereby fix the grommet 10 at apredetermined position on the corrugated tube 33.

Thus, the operation for assembling the wire harness 30 is completed.

Next, an example of an operation for attaching the wire harness 30according to this embodiment to a vehicle body will be described.

First, the wire harness 30 is inserted into the through hole 41 in thewall 40. As shown in FIG. 1, an end of the wire harness 30 is insertedinto the through hole 41 from the outside of the wall 40 and pulled outon the inside of the wall 40. The corrugated tube 33 and thestrip-shaped portion 22, the tapered portion 13, and the inner flangeportion 17 of the grommet 10 pass through the through hole 41 in thisorder. At this time, since the tapered portion 13 and the inner flangeportion 17 of the grommet 10 have tapered shapes that taper toward thefront end, the insertion into the through hole 41 can be easilyperformed. Then, when the outer flange portion 16 abuts against the wallsurface of the wall 40, the circumferential edge portion of the throughhole 41 is sandwiched between the inner flange portion 17 and the outerflange portion 16. In this manner, the main body portion 11 comes intoclose contact with the circumferential edge portion of the through hole41, and the through hole 41 is sealed.

Next, the end portion of the wire harness 30 is connected to a device. Aportion of the wire harness 30 that is disposed inside the vehicle isbent as appropriate. At this time, as shown in FIG. 2, if the corrugatedtube 33 is bent, the strip-shaped portion 22 is pulled up to a side thatopposes the wall 40. Here, the protruding portion 21 that is lined upwith the strip-shaped portion 22 is less likely to deform than the innerflange portion 17, deformation of the inner flange portion 17accompanying the deformation of the strip-shaped portion 22 issuppressed. Then, the terminal fitting at the end portion of the wireharness 30 is connected to the device.

Thus, the operation for attaching the wire harness 30 is completed.

Next, the effects of the embodiment that is configured as describedabove will be described.

The grommet 10 according to this embodiment has the main body portion11, which is fitted into the through hole 41 in the wall 40 and comesinto close contact with the circumferential edge portion of the throughhole 41, the through space 12, which is open in the same direction asthe penetrating direction of the through hole 41, is formed in the mainbody portion 11, and the reinforcement member 25, which suppressesinward distortion of the main body portion 11, is provided in thethrough space 12. With this configuration, the shape of the main bodyportion 11 is maintained by the reinforcement member 25, and uniformadhesion to the circumferential edge portion of the through hole 41 ismaintained over the entire circumference. Thus, the deterioration ofwaterproofness can be prevented.

Moreover, since the reinforcement member 25 is the corrugated tube 33that passes through the main body portion 11, the sheathing memberprotecting the wire harness 30 can be used as the reinforcement member25. Thus, a dedicated component serving as a reinforcement member neednot be produced separately, and an increase in the number of componentscan be prevented. Moreover, the shape of the main body portion 11 can bemaintained and deterioration of waterproofness can be prevented simplyby performing a straightforward operation of inserting the corrugatedtube 33 into the through space 12 of the main body portion 11.

Furthermore, the outer circumferential surface of the corrugated tube 33is in close contact with the inner circumferential surface of the mainbody portion 11. With this configuration, a liquid-tight joint can beobtained between the grommet 10 and the corrugated tube 33 withouthaving to perform a conventional operation of fixing an end portion of acorrugated tube to a grommet.

OTHER EMBODIMENTS

The present disclosure is not limited to the foregoing embodiment thathas been described above and illustrated in the drawings, and, forexample, the following embodiments are also embraced within thetechnical scope of the present disclosure.

(1) In the foregoing embodiment, a case where the reinforcement member25 is the corrugated tube 33 has been described. However, the presentdisclosure is not limited to such a case, and a molded product, otherthan a corrugated tube, that is formed of resin or metal separately froma grommet may also be used as a reinforcement member.

(2) In the foregoing embodiment, a case where the through space 12 ofthe main body portion 11 has a circular cross-sectional shape has beendescribed. However, the present disclosure is not limited to such acase, and a through space of a main body portion may have an ellipticalor oval cross-sectional shape, for example.

(3) In the foregoing embodiment, specific examples of the number, shape,and the like of the lip portions 26 provided in the sealing portion 24have been described. However, the present disclosure is not limited tothese examples, and the number, shape, and the like of lip portions canbe changed as desired.

1. A grommet comprising: a main body configured to fit into a throughhole in a wall and come into contact with a circumferential edge of thethrough hole; and a reinforcement provided in a through space in themain body and configured to suppress inward distortion of the main body,the through space being open in a same direction as a penetratingdirection of the through hole, wherein the reinforcement is cylindricaland conforms to an inner circumferential surface of the main body, andis accommodated in the through space, and the inner circumferentialsurface of the main body includes a second circumferential surface thatis located in close proximity to, or abuts against, an outercircumferential surface of the reinforcement and a first circumferentialsurface that is inclined so that an opening width of the main bodygradually decreases from the second circumferential surface toward anend of the main body in an axial direction thereof.
 2. (canceled)
 3. Thegrommet according to claim 1, wherein the reinforcement is a corrugatedtube that passes through the main body, and an outer circumferentialsurface of the corrugated tube is in close contact with the innercircumferential surface of the main body.
 4. A wire harness comprising:a plurality of wires; a heath that encloses the plurality of wirescollectively; and the grommet according to claim 1.